5.7 It takes a phlebotomist 15 minutes to blood draw. The

supplies for each draw cost $4, and the phlebotomist earns $20

per hour. The phlebotomy lab is designed to accommodate 20,000

draws per year. Its rent is $80,000 per year. What are the average

and incremental costs of a blood draw when the volume is 20,000?

10,000? What principle does your calculation illustrate?

5.8 How would the average and marginal costs change if the

phlebotomist's wage rose to $24 per hour? What principle does your

calculation illustrate?

5.9 A new computer lets a phlebotomist blood draw

in 10 minutes. The supplies for each draw cost $4, and the

phlebotomist earns $20 per hour. The phlebotomy lab is designed

to accommodate 20,000 draws per year. Its rent is $80,000 per year.

What is the marginal cost of a blood draw? What principle does your

calculation illustrate?